Development of a "Dual Gates" Locked, Target-Triggered Nanodevice for Point-of-Care Testing with a Glucometer Readout

Developing a facile and sensitive sensing platform is of importance for point-of-care testing (POCT). Herein, a sensitive and portable POCT platform based on "dual gates" aminated magnetic mesoporous silica nanocomposites (AMMS) bearing polydopamine (PDA)-aptamer (Apt) two-tier shells, as a novel nanodevice, is designed for target detection through a target-triggered glucose (GO) release from AMMS with personal glucometer (PGM) readout. In the absence of target, GO can be firmly captured in pores by the designed "dual gates", which would decrease the high background signal of this system and ensure the accuracy of the detection results. Upon the introduction of the target molecules under acidic conditions (pH 5.5), the subsequent PDA self-degradation and the specific Apt-target reaction can cause the departure of "dual gates" and the opening of pores to release the loaded GO molecules, which could be quantitatively monitored by a portable PGM. It has been demonstrated that such POCT platform shows high sensitivity and excellent selectivity for aflatoxin B1 (AFB1) detection, accompanied by the well-presented reproducibility and stability. Importantly, this sensing platform was further validated by assaying contaminated samples, where the obtained results were well matched with that by HPLC. Regarding the features of portability, high sensitivity, and high throughput detection, the developed platform might find wide applications in POCT.